Car: '94 T/A, 6 spd, stock

Situation: With engine temps up (200 deg. +), the car starts to buck when there is more than about 30% throttle input. First starts only at very low RPM (like under 2000) then as it warms up more it is more or less across all RPMs.

I'm going to check/replace EGR valve in case it is stuck. Don't really think that it is Opti because it is fine when not too hot or with low TPS%.

Any thoughts/ideas would be appreciated.

Thanks,
Todd